I agree with kerrim and axlsdaddy...
LA 1 - arrived around 6:15pm, got into the arena by 6:30, was 4 people off the rail on south side (edge's side) where the catwalk meets the e stage. fantastic views of the band and far enough back to see the screen when necessary.
LA 2 - arrived around 7:15, got into the arena by 7:25, was 4 people off the rail on north side (adam's side) at the end of the e stage. again, amazing views of the band and then was far enough back to see the screen. walked up towards the i stage in time for COBL, stayed there the rest of the show and was still only about 10 people off the rail.
the arenas seem to be big enough and they're handling the amount of GA sales well enough that it's not packed, everyone has space to move around and you only need to get there super early if you want a rail spot or if it's a weekend (it may have helped that LA 1 & 2 were week nights).
have tickets to LA 4, hoping to snag some GAs for LA 3 & 5...